I went to drive the IS300 today and the A/C was blowing hot air. It was working perfectly fine the previous time I drove it (which was about a month ago). I'm hoping it just needs a recharge since it was sitting for a while and working perfectly before. Anyways, I used a gauge that came with a recharge can and it showed that the pressure was high with the A/C on. The clutch does visibly engage and disengage when the A/C is turned on and off respectively so I'm wondering why the gauge shows the pressure being so high on the low side port. The gauge shows high when the A/c is on and off, which has be concerned because the 'Ez Chill' instructions state to take it to a mechanic if it shows high with the A/C on. Does the Lexus/Toyota/IS300 compressor have a special feature which won't let the compressor turn on if its low on refrigerant? The sight glass near the headlight doesn't show bubbles (or possibly nothing at all). Would a simple recharge solve this issue or is there a mechanical issue with the compressor?

If the refrigerant and peg is low, any DIY solutions which don't involve those off-the-shelf leak sealer refrigerants?

It may have a variable displacement compressor which is stuck at zero displacement. If there is saturated pressure on the low side that doesn't drop when the compressor starts, something is wrong with the compressor.

Some high-end Toyotas had a suction throttling valve in between the evaporator and compressor, which does about the same thing as a variable compressor. If you're measuring the pressure before the valve, it could be stuck closed.

From my research, the IS300 has a duel pressure switch (which I assume it means that the compressor won't turn on if the pressure is too high or too low?). Would the high pressure still indicate a faulty compressor?

You said that the compressor does turn on though. So the pressure is OK to start the compressor.

The pressure is supposed to change after the compressor starts. You said it does not do that.

If all the refrigerant leaks out, the switch will open and the compressor won't turn on. In a TXV system which is almost certainly what you have, the switch stays closed at all times in normal operation.

If the system has not had a recharge before & the low side is high with the AC on, then the compressor shaft is probably broken & the gauge reading you see is the normal static pressure of 70-85 psi. Both high & low sides are the same psi. Does the AC button led blink when the system is on? If it is blinking, then the compressor revolution sensor sees not rotation of the shaft & will disengage the clutch.

Do the underhood fans come on when you turn on the ac? If the pressure is too low the compressor will not turn on. Poke the schraeder valve to see if there is any refrigerant in the system (use caution).

Do the underhood fans come on when you turn on the ac? If the pressure is too low the compressor will not turn on. Poke the schraeder valve to see if there is any refrigerant in the system (use caution).

Yes the fans do come on. Should I poke the pin the in the high or low schrader valve?